2.4.1 Wide area monitoring systems

Wide area monitoring systems (WAMS) are an emerging paradigm, involving the utilization of system-wide information to prevent the propagation of large disturbances, increasing the efficiency of the transmission system, and providing better protection and control [8]. Their development was possible thanks to the diffusion of advanced measurement systems: the phasor measurement units (PMU) that are the basic elements of WAMS.

The main difference between these sensors and the supervisory control and data acquisition (SCADA) systems is that they are all synchronized to a common reference time, and thus they can measure and compare the phase angles from voltage phasors of busses contained in a wide area control region. They allow a series of useful applications: state estimation, voltage stability control, dynamic thermal rating, congestion management, and fault localization.

The path toward a smarter grid implies the deployment of WAMS in power systems worldwide.

## 2.4.2 Smart meters

Smart meters are advanced energy meters that offer a wide range of functions, such as storage of detailed consumption data, two-way communication with utilities, and support for dynamic pricing, enabling demand response and monitoring of power quality and disturbance events. A proper deployment of such systems requires an automated metering infrastructure (AMI) that is a two-way communication network linking a huge number of smart meters.

Through AMIs, utilities can improve their analytic capabilities and operate systems in a more efficient, economic, and reliable way. Despite the benefits, AMIs could expose the system to a series of cyber security and customer's privacy threats; thus, they must be carefully designed in order to ensure the protection against cyberattacks.

### 2.5 Distribution domain

Distribution domain is electrically connected to the transmission domain and to the customer's domain. It is at lower voltage levels, and it is where most of the distributed generation has been installed during the last years.
